CVE-2025-39963 remediation guide
Linux Linux, linux kernel
In the Linux kernel, the following vulnerability has been resolved: io_uring: fix incorrect io_kiocb reference in io_link_skb In io_link_skb function, there is a bug where prev_notif is incorrectly assigned using 'nd' instead of 'prev_nd'. This causes the context validation check to compare the current notification with itself instead of comparing it with the previous notification. Fix by using the correct prev_nd parameter when obtaining prev_notif.
Identify the affected asset
Confirm whether Linux Linux, linux kernel is installed, record the deployed version and installation path, and identify exposed interfaces.
- Record the product name, package or appliance identifier, and installed version.
- Identify internet-facing, administrative, API, and internal access paths.
- Preserve the pre-change configuration and relevant service logs.
Validate the affected-version match
Compare the deployed version with the affected range: >= 6fe4220912d19152a26ce19713ab232f4263018d < a89c34babc2e5834aa0905278f26f4dbe4b26b76, >= 6fe4220912d19152a26ce19713ab232f4263018d < 50a98ce1ea694f1ff8e87bc2f8f84096d1736f6a, >= 6fe4220912d19152a26ce19713ab232f4263018d < 2c139a47eff8de24e3350dadb4c9d5e3426db826, >= 6.10, >= 6.10 < 6.12.49, >= 6.13 < 6.16.9, 6.17. Treat incomplete inventory results as unresolved.
Prioritize with independent signals
The CVSS severity warrants an early asset and exposure review. Combine this signal with asset criticality, exposure, compensating controls, and business impact.
Apply supported remediation
Follow the vendor advisory or supported update path. Current fixed-version status: 6.12.49, 6.16.9. Preserve configuration and rollback material before change.
Verify the result
Confirm the resulting version, service health, authentication and access paths, monitoring coverage, and relevant security logs.
- Confirm the expected version and package state.
- Run a functional health check for critical service paths.
- Review authentication, error, application, and security monitoring logs.
- Reassess exposure if the supported fix cannot be applied.
Operational boundary
This page does not replace the vendor advisory, support contract, change-management process, or recovery plan. Do not infer that an asset is unaffected from an incomplete inventory query or a missing fixed-version field.